This invention relates generally to line boring machines which bore holes in a work piece from a side of the work piece resting on a bed, and more particularly, to machines which have a lever mechanically attached to both a clamp and a drill so as to advantageously produce a self-adjusting downward clamp force on the work piece which is always greater than an upward drill force.
In manufacturing, a block of metal or a piece of wood is formed into a useful shape. For example, in a wood cabinet with adjustable shelves, the same may have side panels with a series of bored holes. The holes are used to insert pins such that the shelf may rest thereon to make a shelf height adjustable. To this end, the bored holes are commonly drilled out. When the holes are drilled from above, wood chips tends to clog up the holes. Typically, a drill bit has flutes to allow the chips to exit the holes. Nonetheless, the chips rest on a top surface of the side panels. In this regard, the chips may re-enter the hole and/or may visually block the hole from an operator of the drill. As such, the operator must frequently clear off the chips from the side panels prior to continuing the process of drilling. To alleviate the problem of continually clearing out the holes, the holes would be automatically cleared out if the holes were drilled from a bottom side of the side panel because gravity would clear the holes through gravitational forces.
Currently, machines exist where the work piece rests on a bed, and drills are located below the work piece and bed and traverse upwardly to make holes in the side panels. In this regard, the wood chips are cleared from the holes through gravitational forces. These machines typically have a push down clamp which applies a downward clamp force to the work piece such that the work piece does not lose stability in relation to a bed when the work piece is being drilled from its underside. In these machines, the power which traverses the drill between an up position and a down position is independent from the power which provides the downward clamp force exerted by the clamp.
This dual system of power transmission is inefficient because it requires constant adjustment and more parts. In particular, an upward drill force is exerted on the work piece by the drills and is a function of the number of drills. If a plurality of drills were to simultaneously drill holes from the underside of the side panel then the drill upward force may be greater than the downward clamp force because of the dual system. This situation would cause the work piece to lift off the bed and become unstable thereby the holes may not be properly positioned. In response, the operator must continually adjust (i.e., increase or decrease) the downward clamp force when the number of drills are changed or when the upward drill force changes.
Accordingly, there is a need in the art for an improved apparatus to alleviate the problems of the prior art such as the need to constantly adjust the downward clamp to be greater than a upward drill force and the additional parts to support the dual system.